Insulating a pole barn (questions)

I have a 32×34 pole-barn/garage that is not insulated. It’s all steel sheeted (roof and walls). Poles are 8’ on center. Walls are 9’ tall. There is no attic (open to the roof), and there is a ridge vent along the entire peak. There is no soffit vents.

I’d like to add some heat to the space in the winter, so I can do some hobby woodworking. In the summer I get the full space as my shop, but in the winter we move the cars in, so I condense my shop to the back half. I do not use it often in the winter for woodworking. However, I want to start using it more….

We live in Iowa. I do not want or need to heat it continuously – only when I’m using it (maybe 1-2x/week for a few hours) – only need to heat enough to keep the chill off while working, however, It would be nice to be able to raise the temp if I ever wanted to paint or finish out there. I’m not sure how I want to heat it yet (electric heater, wood stove, furnace, etc, etc), but figured I’d start by insulating it.

This is not our “forever” home, and definitely not my “forever” shop, so I do not want to spend thousands of dollars spray foaming it, etc. We might only be in this home another 5 years, so I can’t justify spending a lot of money on heating/insulating the shop for 1x/week use during the winter months.

~~ROOF~~

I know in pole barns, we have to worry about condensation on the steel. For the roof, I was just going to staple some R13-faced insulation up between the purlins. Do I need to leave the space for the ridge vent open and uninsulated for air movement? Will this allow too much heat to escape? Do I need a moisture barrier of some kind?

~~WALLS~~

I was just going to get some R-8, 1.5” white foam board to put between the girts. Was thinking 1.5” because then it won’t protrude out from the girts and would fit behind the poles. (I do not want to stud out the walls and add interior paneling). Again, do I need a vapor barrier or anything on the walls?

I know these aren’t ideal R-values, but hoping they’d be adequate for some intermittent heating of the shop in the winter. I’d appreciate any ideas, thoughts, advice that you guys might have!! Thanks in advance!

-- Hey you dang woodchucks, quit chucking my wood!!!!

14 replies so far

It’s hard to do it right, and “on the cheap” at the same time. The short answer to most of your questions is Yes, in my opinion. Yes, you need to keep the ridge vent open. Yes, you will lose a lot of heat that way. Yes, you should have a vapor barrier. Yes, all of that will cost $$ to do correctly.

In the short term, your idea of filling the void space between the framing with foam is probably as good as any. I would use rigid foam (usually pink, blue, or yellow around here) because it will be more durable. This can be on the walls and roof, really. Fiberglass batts do not work as well without some type of cover (plywood, sheetrock, etc.) to protect them. They insulate just fine, but they’re not really durable and will absorb moisture, tear, sag, etc. Plus the mice tend to make nests in them from my experience.

Because you will be losing so much heat, I’d choose the heat source with the cheapest fuel. Electric will need at least a 240 volt heater, which is not always available. A propane furnace can be pretty easily installed with 110 volt service and a 100 lb. portable propane tank. No ducting would be needed. But gain, fuel will be expensive. A wood stove, if you have a ready supply of cheap fuel, would be my recommendation. It would also provide radiant heat, which will take the chill off much faster and be more effective with less insulation. Convective heat (like with a furnace or forced air electric heater) will be lost right out the ridge vent.

I’ll wrap up saying that upgrading your insulation will be the best bang for your buck.

This may sound crazy…. but what about hanging a tarp horizontally (may need a little bit of framework) at the 8’ level or so to hold the heat down? Otherwise, I think your plan sounds pretty decent. It’s definitely not an ideal situation. I think you’d have to close off the ridge vent. Another thing I’ve found too is that wood burning stoves can crank out a LOT of heat. If you got a pretty decent one, and kept it cookin’, you may not need to insulate at all…

I would put a chip board ceiling in it and blow insulation on top of it. I’d frame the walls and put bats in there and then put chip board on the walls. It will give you a smaller space to heat and have it insulated all the way around.

cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

My plan was to staple R13-Faced Insulation in-between the purlins. The paper facing on the R13 IS a vapor barrier isn’t it? So as long as I tape the seams, not only should that insulate, but it should also create the vapor barrier. Also, if its taped nice and tight, that should help keep mice out – I doubt I’ll have a problem with mice on the ceiling anyways. Since I’m only intermittent heating, would it be okay to insulate where the ridge vent is, and then remove the insulation in the summer? There shouldn’t be a condensation problem in the winter months – right?

By doing it “on the cheap” – I definitely don’t want to do it incorrectly and ruin the steel/wood in the pole barn. I just want to get by with the bare minimum to be able to hold some heat in the building during some winter days. Like I said, its not a forever shop, so I can’t justify spending a lot of money insulating it.

I would put a chip board ceiling in it and blow insulation on top of it. I d frame the walls and put bats in there and then put chip board on the walls. It will give you a smaller space to heat and have it insulated all the way around.

cheers, Jim

- Jim Jakosh

Jim – I want to keep the ceiling open to the roof so I can have more overhead space if needed. I also don’t want to stud out the walls. Just looking to add enough insulation to the pole barn to allow me to run some heat out there when needed.

This may sound crazy…. but what about hanging a tarp horizontally (may need a little bit of framework) at the 8 level or so to hold the heat down? Otherwise, I think your plan sounds pretty decent. It s definitely not an ideal situation. I think you d have to close off the ridge vent. Another thing I ve found too is that wood burning stoves can crank out a LOT of heat. If you got a pretty decent one, and kept it cookin , you may not need to insulate at all…

- PPK

I thought about not insulating at all and just getting a woodturning stove. Maybe have the wood stove outside, and pipe in the heat? Just didn’t think it’d be worth it, if I didn’t have a way to trap the heat (with insulation). Maybe I should just insulate the back half of it (where my tools will be) and drape some moving blankets down from the rafter to separate the insulated vs non insulated parts. Then I’d only have to heat half the garage while I’m working out there…..

Here’s another hiccup….... the purlins are spaced 20” apart. So I can’t use standard 15” wide insulation. I would have to jump up to the 23”, which means I’d be squeezing it in there tighter, which I know decreases some of the R value….

If i used a foam board up between the purlins, would I still need to put a moisture barrier there? Isn’t the point of the ridge vent to get rid of moisture, so is moisture barrier needed?

This might be overkill but the owner of a hauling company wanted an insulated workshop that was big enough to hold 4 dump trucks. Fiberglass Insulation 6” thick in the walls and ceiling. The insulation was covered on the inside walls with ‘bright’ galvanized steel that would normally be used on outside walls and roof. Also insulated 12’ tall doors to get the trucks in without issue. Proof of success was that a small woodstove could heat the garage to shortsleeve temperatures when outside temps were 0F in a matter of few hours.

So you might want to insulate a portion of your pole-barn/garage to get the same effect.

for pole barns they have giant batts that you fasten up top and essentially let hang in between poles. You could probably use the same product for your ceiling, just have to put some 2×4 to hold it in place.

I think I may be qualified to speak on this subject since I have spent a few sub zero winters in Iowa and my shop is about the same size (30×36). Having tried several methods of heating a free standing shop I will weigh in. When building my shop a contractor gave me a wood burner he had acquired in a remodel. Wood is by far the cheapest fuel source (if you can cut and split your own wood and let it dry for a year, but a lot of work) Even with a free wood burner the cost of double walled flue pipe was almost $2000. I figured I could buy an awful lot of propane for 2 Gs so I have been using a ventless wall mounted propane heater for the past few years. I use about 2-3 75lb propane tanks per winter but I only heat when I’m in the shop, cost is about $80-90 per tankful The rest of the time I use a small oil filled electric heater to keep the shop just warm enough to keep liquids from freezing. I got an air handler (electric furnace, another free-bee) a few years back. Heated the shop to a toasty temp but the electric bill was just too much. My son works for an HVAC wholesaler and last month I got a minisplit which is almost installed. This is a small one room heat pump which also cools in the summer. I’m hoping this will serve both my summer and winter needs but these require an additional heat source in really cold temps. I agree with some of the other posts, what ever you do your going to have to fork up some $ for insulation. A large sheet of plastic will serve as a necessary vapor barrier. You’ll never be able to get a metal building warm enough in the dead of winter even with a ton of BTUs. Try Craigslist under materials, I have seen a lot of styrofoam insulation for sale cheap on there. Good luck

-- Common sense is so rare anymore when you do see it, it looks like pure genius.

I would hang 4×8 sheets of insulation across the purlins and not insulate the walls. Heat goes up so most of ur heat lost will be the ceiling since hot air goes up. Put a wood stove in the building and build a fire about and hour before you wanna do work and it’ll b plenty good to knock the chill off a little. Its cheap to do and the next owner and either rip it all out or live with it.